Halogenated esters as herbicide antidotes

ABSTRACT

Herbicidal compositions comprising an active herbicidal compound and antidote therefor and the methods of use; the antidote compounds correspond to the halogenated esters having the formula   wherein R1 is lower haloalkyl, alkynyl, alkenyl and N,Ndialkenylaminoalkyl and R2 is lower haloalkyl.

United States Patent Pallos July 8, 1975 [54] HALOGENATED ESTERS ASHERBICIDE 3,564,768 2/1971 Hoffman 71/79 ANTIDOTES 3,719,466 3/1973 Ahle71/88 [75] Inventor: Ferenc M. Pallos, Walnut Creek,

Calif.

[73] Assignee: Stauffer Chemical Company,

Westport, Conn.

[22] Filed: Nov. 16, 1972 [21] Appl. No.: 307,277

[52] U.S. Cl. 71/100; 71/79; 71/106 [51] Int. Cl A01n 9/12 [58] Field ofSearch 71/79, DIG. 1, 100, 106

[56] References Cited UNITED STATES PATENTS 2,913,327 11/1959 Tilles eta1. 71/100 3,095,299 6/1963 Luckenbaugh 71/100 3,131,509 5/1964 Hoffman71/79 Primary ExaminerJames 0. Thomas, Jr. Attorney, Agent, orFirm-Harry A. Pacini; Daniel C. Block; Edwin H. Baker [5 7] ABSTRACTHerbicidal compositions comprising an active herbicidal compound andantidote therefor and the methods of use; the antidote compoundscorrespond to the halogenated esters having the formula wherein R islower haloalkyl, alkynyl, alkenyl and N,N-dialkenylaminoalky1 and R islower haloalkyl.

11 Claims, No Drawings HALOGENATED ESTERS AS HERBICIDE ANTIDOTESBACKGROUND OF THE INVENTION Among the many herbicidal compoundscommercially available, the thiocarbamates alone or admixed with otherherbicides, such as the triazines, have reached a relatively high degreeof commercial success. These herbicides are immediately toxic to a largenumber of weed pests at different concentrations varying with theresistance of the weed pests. Some examples of these compounds aredescribed and claimed in US. Pat. Nos. 2,913,327, 3,037,853, 3,175,897,3,185,720, 3,198,786 and 3,582,314.

It has been found in practice that the use of these thioearbamates asherbicides on crops sometimes causes serious injuries to the crop plant.When used in the recommended amounts in the soil to control manybroadleaf weeds and grasses, serious malformation and stunting of thecrop plants result. This abnormal growth in the crop plants results inloss of crop yield. Previous attempts to overcome this problem involvesthe treatment of the crop seed with certain antagonistic agents prior toplanting, see U.S. Pat. Nos. 3,131,509 and 3,5 64,768. Theseantagonistic agents have not been notably successful. The aforementionedpatent specifically exemplifies the treatment of seeds employingcompounds of a different chemical class not suggestive of the presentinvention.

DESCRIPTION OF THE INVENTION It has been discovered that plants can beprotected against injury by various herbicides, for example, thethiocarbamate-type herbicides, alone or mixed with other herbicidalcompounds and/or the tolerance of the plants can be substantiallyincreased to the active compounds of the above-noted US. patents byadding to the soil an antidote compound corresponding to the followingformula R|OCR- wherein R is lower haloalkyl, alkynyl, alkenyl andN,N-dialkenylaminoalkyl and R is lower haloalkyl.

In the description of the halogenated esters as compounds useful in theherbicidal antidote method of this invention, the following embodimentsare intended for the various groups: The term halo preferably refers tofluoro, chloro and bromo substitutions in mono, di, tri, tetra and persubstitution. Halo also is intended to relate to mixed halogensubstitution, such as in dichloromonofluoromethyl and the like. Alkynylpreferably includes those members having at least one carbonto-carbontriple bond and from 3 to 6 carbon atoms, inclusive. The term alkenylpreferably includes those members having at least one carbon-to-carbondouble bond and from 3 to 6 carbon atoms, inclusive. In the termN,N-dialkenylaminoalkyl, the alkyl moiety preferably includes thosemembers having 1 to 4 carbon atoms, inclusive, alkenyl is as definedhereinabove. The term lower haloalkyl preferably has halo-substitutionas denoted above and lower alkyl moiety having from 1 to 4 carbon atoms,inclusive, for example, monochloromethyl, monobromomethyl,monofluoromethyl,

dichloromethyl, dibromomethyl, 1,1-dichloroethyl, l ,2-dichloroethyl,1,1,l-trichloroethyl, dichloromonofluoromethyl, l-chlorobutyl,l-fluorobutyl, 1- bromobutyl, 1,4-dichlorobutyl and the like.

As an alternative mode of action, the compounds of this invention mayinterfere with the normal herbicidal action of the thiocarbamate-typeand other herbicides to render them selective in their action. Whichevermode of action is present, the corresponding beneficial and desirableeffect is the continued herbicidal effect of the thiocarbamate with theaccompanying decreased herbicidal effect on desired crop species. Thisadvantage and utility will become more apparent hereinafter.

Therefore, the terms herbicide antidote or antidotal amount, is meant todescribe that effect which tends to counteract the normal injuriousherbicidal response that the herbicide might otherwise produce. Whetherit is to be termed a remedy, interferant, protectant, or the like, willdepend upon the exact mode of action. The mode of action is varied, butthe effect, which is desirable, is the result of the method of treatingthe soil in which a crop is planted. Hitherto, there have been nosystems which have been satisfactory for this purpose.

The compounds of this invention represented by the above formula can beprepared by several different procedures depending upon the startingmaterials.

The reaction of a halogen-containing chloride with an alcohol to form anester is well known. The same general method is used in the preparationof the compounds of this invention; however, certain modifications ofthe reaction have been made to simplify the procedure and to insure inmost instances high yields. The modifications include the use of asolvent such as benzene or methylene chloride; the use of a hydrogenchloride acid acceptor such as triethylamine. After completion of thereaction, the product is conveniently isolated by conventionaltechniques.

The following examples, which are illustrative of the compounds usefulin the instant invention, should not be construed as limiting examples,variations and modifications thereof will be apparent to one havingordinary skill in this art.

EXAMPLE I Preparation of 2-bromoethyl dichloroacetate Dichloroacetylchloride (7.4 g., 0.05 mole) was dissolved in 200 ml. benzene,2-bromoethanol (6.2 g., 0.05 mole) was added. Triethylamine (5.1 g.,0.05 mole) in 10 ml. benzene was slowly added. The temperature was keptbelow 30C. After the addition was complete, the resulting solution wasrefluxed for one hour. The reaction mixture was washed with water, driedover magnesium sulfate, filtered and the solvent removed under vacuum.There was obtained 10.6 g. of the title compound, r1 1.4972.

EXAMPLE 11 Preparation of Propargyl dichloroacetate In a similarprocedure as Example I, 2.8 g., 0.05 mole of propargyl alcohol in 40 ml.of methylene chloride was reacted with 7.4 g., 0.05 mole, ofdichloroacetyl chloride in the presence of 5.2 g. triethylamine. Therewas obtained 5.5 g. of the title compound, m, 1.4680.

EXAMPLE III Preparation of N,N-diallylaminoethyl dichloroacetate In asimilar method as described in Example I, 3.5 g., 0.025 mole, ofN,N-diallylaminoethanol in 26 ml. methylene chloride was reacted with3.7 g., 0.025 mole, of dichloroacetyl chloride in the presence of 2.6

g. triethylamine. There was obtained 3.7 g. of the title compound, r11.4700.

The compounds of the present invention and their preparation are moreparticularly illustrated by the following table. Following is a table ofcompounds which are prepared according to the procedures describedherein. Compound numbers have been assigned to them and are used foridentification throughout the balance of the specification.-

The compounds of this invention were employed in effective herbicidalantidote compositions comprising thiocarbamates in combination withantidote compounds described hereinabove.

Corn Seed Treatment Test Small flats were filled with Felton loamy sandsoil. Soil incorporated herbicides were applied at this time. The soilfrom each flat was placed into a S-gallon cement mixer where the soilwas mixed as the herbicides were applied using a predetermined amount ofa stock solution containing 936 mg. of 75.5% active ingredient to 100ml. of water. One ml. of stock solution was applied to the soil in avolumetric pipet for each pound of herbicide desired. One ml. of stocksolution con tained 7 mg. of herbicide which equals one pound per acrewhen applied to the soil in the flats. After the herbicideincorporation, the soil was placed back into the flats.

Flats of herbicide-treated and untreated soil were then ready to beplanted. A pint sample of soil was removed from each flat and placednext to each flat for later use in covering up the seeds. The soil wasleveled and rows one-half inch deep were made for planting seeds.'Alternating rows of treated and untreated crop seeds were sown. In eachtest, six PAG 344T or DeKalb XL3 74 field corn seeds were planted ineach row. Rows were approximately 1 /2 inches apart in the flat. Seedswere treated by placing 50 mg. of the antidote compound with grams ofcorn seed (0.5% w/w) in a suitable container and shaking them until theseeds were uniformly covered with the compound. Antidote compounds werealso applied as liquid slurries and powders or dusts. In some cases,acetone was used to dissolve powdered or solid compounds so they couldbe more effectively applied to the seeds.

After the flats were seeded, they were covered with the 1 pint of soilwhich had been removed just prior to planting. Flats were placed ongreenhouse benches where temperatures ranged from 90F. Flats werewatered by sprinkling as needed to assure good plant growth. Percentcontrol ratings were taken 2, 3 and 4 weeks after the treatments wereapplied.

In each test, the herbicide was applied alone, in combination with theseed protectant, and the seed protectant was applied alone to check forphytotoxicity. The untreated adjacent row was employed to observe anybeneficial lateral movement of the antidote compound through the soil.The degree of the effect was noted by comparison with the control. Theresults of these tests are tabulated in Table II.

TABLE II Percent Injury to Corn from EPTC* Seed Treatment Test PercentInjury, 2 Weeks *EPTC S-ethyl dipropylthiocarbamatc 6E: 6 lb/A pre-plantincorporated The antidote compounds and compositions of the presentinvention can be used in any convenient form. Thus, the antidotecompounds can be formulated into emulsifiable liquids, emulsifiableconcentrates, liquid, wettable powder, powders, granular or any otherconvenient form. In its preferred form, a non-phytotoxic quantity of anherbicidal antidote compound is admixed with a selected herbicide andincorporated into the soil prior to or after planting the seed. It is tobe understood, however, that the herbicides can be incorporated into thesoil and thereafter the antidote compound can be incorporated into thesoil. Moreover, the crop seed itself can be treated with anon-phytotoxic quantity of the compound and planted into the soil whichhas been treated with herbicides, or untreated with the herbicide andsubsequently treated with the herbicide. The addition of the antidotecompound does not affect the herbicidal activity of the herbicides.

The amount of antidote compound present can range between about 0.001 toabout 15 parts by weight of antidote compound described herein per eachpart by weight of herbicide. The exact amount of antidote compound willusually be determined on economic ratios for the most effective amountusable. It is understood that a non-phytotoxic quantity of antidotecompound will be employed in the herbicidal compositions describedherein.

The herbicides indicated in the tables and elsewhere are used at rateswhich produce effective control of undesirable vegetation. The rates arewithin the recommended amounts set forth by the supplier. Therefore, theweed control in each instance is commercially acceptable within thedesired or recommended amount.

It is clear that the classes of herbicidal agents described andillustrated herein are characterized as effective herbicides exhibitingsuch activity. The degree of this herbicidal activity varies amongspecific compounds and among combinations of specific compounds withinthe classes. Similarly, the degree of activity to some extent variesamong the species of plants to which a specific herbicidal compound orcombination may be applied. Thus, selection of a specific herbicidalcompound or combination to control undesirable plant species readily maybe made. Within the present invention are prevention ofinjury to adesired crop species in the presence of a specific compound orcombination may be achieved. The beneficial plant species which can beprotected by this method is not intended to be limited by the specificcrops employed in the examples.

The herbicidal compounds employed in the utility of this invention areactive herbicides of a general type. That is. the members of the classesare herbicidally effective against a wide range of plant species withsome degree of discrimination between desirable and undesirable species.The method of controlling vegetation comprises applying an herbicidallyeffective amount of the hereindescribed herbicidal compounds to the areaor plant locus where control is desired. The compositions as set forthin this invention include those wherein the preferred active herbicidalcompound is selected from S-ethyl dipropylthiocarbamate, S-ethyldiisobutyl thiocarbamate, S-propyl dipropylthiocarbamate, S-2,3,3-trichloroallyl-diisopropyl thiocarbamate, S-ethyl cyclohexy] ethylthiocarbamate, 2-chloro-2',6"- diethyl-N-(methoxymethyl)acetanilide,S-ethyl hexahydrol H-azepine- 1 -carbothioate, 2-chloro-N-isopropylacetanilide, N,N-diallyl-2-chloroacetamide, S-4-chlorobenzyldiethyl thiocarbamate, 2-chloro-4-ethylamino-o-isopropylamino-s-triazine, 2-chloro-4,6-bis(ethylamino)-s-triazine,2(4-chloro-6-ethylamine-striazine-Z-yl-amino)-2-methylpropionitrile,2-chloro-4- cyclopropylamino-6-isopropylamino-s-triazine,2,4-dichlorophenoxyacetic acid, its esters and salts, and 3-( 3,4-dichlorophenyl)-1,1-dimethylurea and combinations thereof.

An herbicide as used herein means a compound which controls or modifiesthe growth of vegetation or plants. Such controlling or modifyingeffects include all deviations from natural development; for example,killing, retardation, defoliation, desiccation, regulation, stunting,tillering, stimulation, dwarfing and the like. By plants it is meantgerminant seeds, emerging seedlings, and established vegetation,including the roots and above-ground portions.

What is claimed is:

l. The method of reducing injury to corn crops in- 10 jured bythiocarbamate herbicides comprising applying to the corn seeds prior toplanting a nonphytotoxic antidotally effective amount of a compoundcorresponding to the formula wherein R, is lower haloalkyl, alkynyl,alkenyl and N,N-dialkenylaminoalkyl and R is lower haloalkyl.

2. The method according to claim 1 in which R, is lower haloalkyl and Ris lower haloalkyl.

3. The method according to claim 2 in which R, is 2- bromoethyl and R isdichloromethyl.

4. The method according to claim 2 in which R, is 2- chloroethyl and Ris dichloromethyl.

5. The method according to claim 1 in which R, is alkynyl and R is lowerhaloalkyl.

6. The method according to claim 5 in which R, is 2- propynyl and R isdichloromethyl.

7. The method according to claim 5 in which R, is 2- butynyl and R isdichloromethyl.

8. The method according to claim 1 in which R, is alkenyl and R is lowerhaloalkyl.

9. The method according to claim 8 in which R, is 2- propenyl and R isdichloromethyl.

10. The method according to claim 1 in which R, isN,N-dialkenylaminoalkyl and R is lower haloalkyl.

11. The method according to claim 10 in which R, isN,N-dialkylaminoethyl and R is dichloromethyl.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 1 3,893 ,838

DATED July 8 1975 |NVENTOR(S) Ferenc M. Pallos It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

In Column 3, Table I, under the column "R the entry for Compound No. 3should read CH CECH In Column 3, Table I, under the column "R the entryfor Compound No. 4 should read CH C'..- -.CCH

Signed and Scaled this Twenty-eighth Day Of December 1976 [SEAL] RUTH C.MASON C. MARSHALL DANN Arresting Officer Commissioner ofParents andTrademarks

1. THE METHOD OF REDUCING IN JURY TO CORN CROPS INJURED BY THIOCARBAMATEHERBICIDES COMPRISING APPLYING TO THE CORN SEEDS PRIOR TO PLANTING ANONPHYTOTOXIC ANTIDOTALLY EFFECTIVE AMOUNT OF A COMPOUND CORRESPONDINGTO TO THE FORMULA R1-OOC-R2 WHEREIN R, IS LOWER HALOLKY, ALKYNYL,ALKENYL AND N, N-DIALKENYLAMINOALKYL AND R2 IS LOWER HALOALKYL.
 2. Themethod according to claim 1 in which R1 is lower haloalkyl and R2 islower haloalkyl.
 3. The method according to claim 2 in which R1 is2-bromoethyl and R2 is dichloromethyl.
 4. The method according to claim2 in which R1 is 2-chloroethyl and R2 is dichloromethyl.
 5. The methodaccording to claim 1 in which R1 is alkynyl and R2 is lower haloalkyl.6. The method according to claim 5 in which R1 is 2-propynyl and R2 isdichloromethyl.
 7. The method according to claim 5 in which R1 is2-butynyl and R2 is dichloromethyl.
 8. The method according to claim 1in which R1 is alkenyl and R2 is lower haloalkyl.
 9. The methodaccording to claim 8 in which R1 is 2-propenyl and R2 is dichloromethyl.10. The method according to claim 1 in which R1 isN,N-dialkenylaminoalkyl and R2 is lower haloalkyl.
 11. The methodaccording to claim 10 in which R1 is N,N-dialkylaminoethyl and R2 isdichloromethyl.